#include<stdio.h>
//int main()
//{
//	int a, b, c = 0;
//	a = 15;
//	b = 20;
//	c = 8;
// int sum=a+b+c;
//	printf("min = %d\n", (a < b ? a : b) > c ? c : (a < b ? a : b));
//	printf("max=%d\n",(a>b?a:b)>c?(a>b?a:b):c);
// printf("middle=%d\n",sum-((a>b?a:b)>c?(a>b?a:b):c)- ((a < b ? a : b) > c ? c : (a < b ? a : b)));
// return 0;
//}
int main()
{
	while (c = getchar() != EOF)
	{
		char c = getchar();
		printf("%c", c);
	}
	return 0;
}